Electrical contacts between an element and a host can be physically large, costly and unreliable. Some elements are consumable, replaceable or removable and it is desired that their cost be lower. One type of such element is a battery pack. It may have only three wires that provide power, ground, and communications. In many cases, it is advantageous to authenticate a battery pack using the communication pin to ensure that it was manufactured by a bona-fide supplier. Such authentication may help to ensure that the battery pack provides the requisite voltage and current for proper operation of the host. Communications via the communications wire should be reliable and fast.
Existing “one-wire” communication protocols are relatively slow and are susceptible to timing variations on the element side of communication transactions. Since data transfer is dependent on the width of pulses sent between the host and element, timing can be a very important to proper communication. Such elements typically do not include a crystal to provide precise timing information beneficial to pulse width coding based communication protocols.